Stereo cartrdge now playing mono!!

Hello lastperfectdaymusic. Have you found a solution to your problem?

If not, the only thing I can recommend is making sure the problem is with the cartridge and not another part of the playback chain. For example, if you swap the left and right channels at your phono preamp, does the same or a different channel play? What about if you swap the leads at the headshell? Or do you have a back-up cartridge you could swap in to see if it plays on both channels?

Hard to really know what to suggest without knowing your full system or what the moving conditions were. If you have tubes, can you rule out that a tube hasn't gone bad?

I don't have a ton of experience with cartridges, but I'd tend to think that, cantilever notwithstanding, there's not a lot to go really wrong within the cartridge itself. I'd want to work back methodically from the last known good component to see if something else might have been upset in the move.

Best of luck - I'll be curious to hear what you learn.

The Decca London had a top that could be removed by sliding it off the cartridge body.  Then you had access to a platform that fixed the position of two of the coils using two set screws that if re-set in unison could move the platform up or down.  By pure ignorance, I and a friend converted our stereo Decca London cartridges to mono, simply by maladjustment of that platform.  No modern cartridge that I know about would by its construction permit the user to do such a thing.  Funnily, both of us thought we had improved the sound, until we each separately realized what we had wrought.